Dry powder seasoning and manufacturing method and apparatus for the same

ABSTRACT

Seasoning of liquid material containing at least sodium chloride, seasoning components and solvent is dried at a temperature not more than the boiling temperature of the liquid material to generate mixture bodies containing large-diameter spherical bodies and small-diameter spherical bodies. Accordingly, the solvent is not rapidly vaporized, but it is slowly vaporized and components dissolved in water, and particularly sodium chloride is not agglomerated on the surface layer portions of the large-diameter spherical bodies, but kept inside the large-diameter spherical bodies. Therefore, segregation of sodium chloride on the surface layer portions can be suppressed, and deliquescence is reduced. Accordingly, there can be obtained dry powder seasoning which is low in deliquescence under a using state and excellent in storage stability for a long term.

TECHNICAL FIELD

The present invention relates to dry powder seasoning manufactured bydrying liquid type seasoning, and method and apparatus for manufacturingthe dry powder seasoning.

BACKGROUND ART

Soy sauce is known as typical liquid-type seasoning which has beenconsumed on a massive scale in Japan. Many kinds of commercial productsof soy sauce such as “koikuchi” (strong) soy sauce, “usukuchi”(light-colored and saltier) soy sauce, “tamari” (thick-tasted) soysauce, “shiro” (white) soy sauce, “saishikomi” (twice-brewed) soy sauce,“ki” (non-pasteurized) soy sauce, “genen” (salt-reduced) soy sauce, etc.are manufactured and sold. Normally-available soy sauce is liquid-typesoy sauce, and it is packed in a container such as a glass bottle, a PETbottle or the like, stocked, transported and then sold. Furthermore, itis divided into a small-size container and used in a small-lot style.However, when the liquid-type soy sauce is stocked and transported, thetransport cost is increased because it has large volume and weight.Furthermore, when it is preserved at a high-temperature place, it trendsto change its nature in a short period of time. Therefore, there is aproblem that the preserving condition is very severe and the taste ischanged under preservation. Accordingly, soy sauce fresh from thebrewery is popularly used. Powder milk and soap of instant noodle, etc.are dried to obtain powder according to a freezing and drying method, aspray drying method or the like so that the volume is reduced, therebyenhancing handling performance and storage stability.

(Concerning Deliquescence)

However, the dried soy sauce has an essential problem.

That is, first, it has a “deliquescent property”. In the case where thedried soy sauce has the deliquescent property, for example when it isleft alone under an atmosphere of about 50 to 60% in humidity under thestate that it is heaped up on a flat-plate type container of about 5cmin diameter, the surface layer of the dried soy sauce absorbs moisturein about 2 to 3 hours under the above state, and the moisture-absorbedportion of the dried soy sauce is hardened along the mountain-likeshape. Accordingly, the dried soy sauce falls into such a state that themoisture-absorbed hardened portion exfoliates from the mountain of thedried soy sauce as if it is like a conical baked cake or scab.Furthermore, when the dried soy sauce is preserved all day and night, itis transformed to sticky paste as a whole and thus it is remarkably hardto be handled.

Secondly, it is substantially difficult to put fine powder of dried soysauce into a small container and use it as a powder sparingly likesprinkle due to the deliquescent property or the moisture absorptionproperty described above. As described above, the surface layer isagglomerated and solidified like scab due to the moisture absorption fora short time as described above, and thus the take-out port of thecontainer is clogged in a short period of time.

Thirdly, when the dried soy sauce is returned to original liquid, thetaste of the soy sauce greatly varies. If it is stocked for a long term,it would grow musty and turn stale.

Particularly, a large amount of “excipient” has been hitherto added tomanufacture dried soy sauce in a powdery form, and thus the taste of thedried soy sauce varies when the dry powder soy sauce is returned to theoriginal state.

(Drying Method)

A drying-by-heating method is frequently used for powdery seasoning suchas powder milk, soap of instant noodle, etc. and chemicals. A spraydrying machine (spray dryer) is frequently used as a drying machine forimplementing the above drying method.

Furthermore, a pressure-reduced dram drying method, a vacuum-freezedrying method or a spray drying method is used as a method of drying soysauce, and the spray drying method is most preferable. A pressurizednozzle type spray dryer, a two fluid nozzle type spray dryer, adesk-atomizer type spray dryer, a spray-drying and granulating dryer orthe like is used as a preferable machine used for the spray dryingmethod (see non-patent document 1, patent documents 1 and 2).

It has been hitherto general that high-pressure air and soy sauce aresprayed into a drying tower in which hot air is supplied from the upperside to the lower side, or miniaturized soy sauce is discharged under adispersion state by a rotating disc and then atomized liquid droplets ofsoy sauce are heated to be dried. In this case, the hot air is set to120° C. to 200° C., and high-temperature heating air of 260° C. isadopted in consideration of efficiency.

Non-patent Document 1: “Base and Application of Dried food” issued byKabushikikaisha Saiwaishobo on Sep. 1, 1997, pp 92-94

Patent Document 1: JP-A-2004-105066 Patent Document 2: JP-A-7-213249DISCLOSURE OF THE INVENTION Problem to be solved by the Invention

In general, dextrin is added as “excipient” so that soy sauce is used asraw material and it is dried to form dry powder soy sauce. This isbecause it is impossible to manufacture granular dry powder soy saucehaving desired size when no excipient is used. However, the excipient isa material having an excellent property which enhances water solution ofpowder, and thus greatly contributes to deliquescence. Accordingly, theconventional dry powder soy sauce contains a large amount of dextrin, sothat it is deteriorated in storage stability and it is not used in suchan application that a lid is opened and closed. In addition, when wateris added to dry powder soy sauce containing dextrin to return the drypowder soy sauce to the original liquid, the components thereof becomedifferent from those of the original soy sauce, and thus the taste isdifferent from the original taste, so that deterioration of quality isunavoidable.

Furthermore, dry powder manufactured by using the conventional spraydryer and high-temperature hot air contains a slight quantity ofmoisture (about 2 to 3%) in the solid content thereof, and most ofmoisture which existed as soy sauce was evaporated. However, this drypowder soy sauce has deliquescence and it absorbs moisture in a shortperiod of time as described above.

Therefore, an object of the present invention is to solve the aboveproblem of the conventional techniques described above, and provide drypowder seasoning that has low deliquescence when it is used andexcellent storage stability for a long term, a method of manufacturingthe dry powder seasoning and a method of manufacturing the dry powderseasoning.

Means of solving the Problem

In order to solve the above problems, according to the presentinvention, dry powder seasoning is characterized by comprising mixturescontaining large-diameter spherical bodies and small-diameter sphericalbodies generated by drying seasoning of a liquid material containing atleast sodium chloride, seasoning components and solvent under atemperature which is not more than the boiling temperature of the liquidmaterial so as to suppress segregation of sodium chloride on surfacelayer portions of the large-diameter spherical bodies.

According to the present invention, by drying the seasoning at theboiling temperature of the liquid material or less, the solventconstituting the liquid material is not rapidly vaporized, but slowlyvaporized.

Therefore, when the large-diameter spherical bodies are formed, watervapor slowly moves from the inside of the large-diameter sphericalbodies to the outside thereof, and is slowly discharged from thesurfaces. Therefore, the components dissolved in the moisture,particularly sodium chloride is not assembled on the surface layerportion, and can be kept inside the large-diameter spherical bodies.

Accordingly, crystallization caused by consolidation of sodium chlorideis not promoted, and thus segregation of sodium chloride on the surfacelayer portions of the large-diameter spherical bodies can be suppressed,so that deliquescence can be kept to a low level.

In this case, preferably, chlorine and sodium may be distributed under asubstantially uniform dispersive state to suppress the segregation ofsodium chloride. Furthermore, more preferably, the seasoning of theliquid material may be dried at a temperature which is not more than theazeotropic point of alcohol and water contained in the solvent togenerate the mixture bodies of the large-diameter spherical bodies andthe small-diameter spherical bodies.

In this construction, by drying the seasoning at a temperature which isnot more than the boiling temperature of alcohol and water contained inthe solvent, alcohol and “umami” components dissolved in alcohol aresuppressed from being lost due to evaporation of alcohol, and the“umami” components and alcohol can be kept in the large-diameterspherical bodies and the small-diameter spherical bodies, so that thedry powder seasoning can keep a taste closer to the taste of theraw-material seasoning.

Furthermore, preferably, the surface portions of the large-diameterspherical bodies may be formed to have smooth surfaces having no rift.

Still furthermore, preferably, the moisture content of each mixture bodymay be in the range from 4% to 12% by weight.

Still furthermore, the diameter of the large-diameter spherical bodiesmay be equal to 40 μm or more.

Furthermore, a method of drying seasoning of a liquid materialcontaining at least sodium chloride, seasoning components and solvent tomanufacture dry powder seasoning, is characterized by comprising:spraying the seasoning of the liquid material into a drying tower so asto obtain fog drips of the seasoning, the drying tower being controlledso that the temperature in the main body of the tower is not more thanthe boiling temperature of the liquid material and the temperature of aninner wall surface thereof at a high place is lower than the temperatureof an inner wall surface thereof at a low place; and drying the fogdrips while the fog drips are convected vertically in the drying tower.

In this case, preferably, the temperature in the drying tower may becontrolled so that the temperature concerned is not more than theazeotropic point of alcohol and water contained in the solvent, and theseasoning of the liquid material may be sprayed into the drying tower soas to obtain fog drips of the seasoning.

More preferably, a temperature difference may be provided to the innerwall surface of the main body of the drying tower, and ascending currentmay be generated along the inner wall surface by using the temperaturedifference.

Furthermore, an apparatus for drying seasoning of a liquid materialcontaining at least sodium chloride, seasoning components and solvent tomanufacture dry powder seasoning is characterized by comprising: adrying tower; a raw-material seasoning spraying unit disposed at anupper portion of the main body of the drying tower; a raw-materialseasoning supply device having a temperature control function that isconnected to the spraying unit; a cyclone connected to a lower portionof the main body of the drying tower to separate power dry soy sauce; agas exhaust device for keeping the inside of the cyclone under apressure-reduced state; a heating unit such as an electric heater or thelike provided to the outer surface of the main body of the drying tower;a temperature sensor for measuring the temperature of a required placeof the main body of the tower; and a controller for controlling aheating state of the heating unit so that the temperature in the mainbody of the tower is not more than the boiling temperature of the liquidmaterial and the temperature of an inner wall surface thereof at a highplace is lower than the temperature of an inner wall surface thereof ata low place.

Accordingly, in the apparatus of this invention, by drying the seasoningat the boiling temperature of the liquid material or less, the solventconstituting the liquid material is not rapidly vaporized, but slowlyvaporized.

Therefore, when the large-diameter spherical bodies are formed, watervapor slowly moves from the inside of the large-diameter sphericalbodies to the outside thereof, and is slowly discharged from thesurfaces. Therefore, the components dissolved in the moisture,particularly sodium chloride is not assembled on the surface layerportion, and can be kept inside the large-diameter spherical bodies.

Accordingly, crystallization caused by consolidation of sodium chlorideis not promoted, and thus segregation of sodium chloride on the surfacelayer portions of the large-diameter spherical bodies can be suppressed,so that deliquescence can be kept to a low level.

In this case, preferably, the controller may control the heating stateof the heating unit so that the temperature in the main body of thedrying tower is not more than the azeotropic point of alcohol and watercontained in the solvent, and the temperature of the inner wall surfacethereof at the high place is lower than the temperature of the innerwall surface thereof at the low place.

In this construction, by drying the seasoning at a temperature which isnot more than the boiling temperature of alcohol and water contained inthe solvent, alcohol and “umami” components dissolved in alcohol aresuppressed from being lost due to evaporation of alcohol. Accordingly,the large-diameter spherical bodies or the small-diameter sphericalbodies can keep the “umami” components and alcohol, and thus there canbe manufactured the dry powder seasoning which keeps a taste closer tothe taste of the raw-material seasoning.

Furthermore, more preferably, the inner wall surface of the main body ofthe drying tower is subjected to water repellent finishing such assilicon finishing, fluorocarbon resin finishing or the like to preventadhesion of droplets to the inner wall surface of the main body of thedrying tower.

Furthermore, further preferably, a ceramic layer having a double-layerstructure which contains an aluminum-oxide spray layer mainly containingaluminum oxide and a titan-oxide spray layer mainly containing titanoxide formed on the aluminum oxide spray layer may be formed on theouter surface of the main body of the drying tower, and the heating unitmay be disposed on the outer surface of the titan-oxide layer.

Still furthermore, preferably, the heating unit is disposed in each ofat least three areas sectioned in the longitudinal direction of the mainbody of the drying tower through an electrically insulating layer on theceramic layer having the double structure formed on the outer surface ofthe main body of the drying tower, and the controller controls thetemperature of each of the heating units independently.

Effect of the Invention

According to this invention, mixtures containing large-diameterspherical bodies and small-diameter spherical bodies are generated bydrying seasoning of a liquid material containing at least sodiumchloride, seasoning components and solvent under a temperature which isnot more than the boiling temperature of the liquid material. Therefore,segregation of sodium chloride on surface layer portions of thelarge-diameter spherical bodies can be suppressed in the process ofgenerating the mixture bodies, and the components causing deliquescencehardly comes into contact with air, or protected from being exposed, sothat the deliquescence under the use state can be reduced, and thestorage stability for a long term can be enhanced.

BRIEF DESCRIPTION OF THE DRAWINGS

{FIG. 1] is a diagram showing an example of an apparatus forimplementing the present invention.

[FIG. 2] (A) is a diagram showing the flow of an air current in a dryingtower shown in FIG. 1, and (B) is a diagram showing an occurrence stateof a mixture stream in the drying tower shown in FIG. 1.

[FIG. 3] is a partially cross-sectional view showing the main body ofthe drying tower.

[FIG. 4] is a partially cross-sectional view showing the main body ofthe drying tower.

[FIG. 5] is a longitudinally sectional view of a nozzle.

[FIG. 6] is a V-V cross-sectional view of FIG. 5.

[FIG. 7] is a cross-sectional view of the nozzle.

[FIG. 8] is a longitudinally-sectional view of the nozzle.

[FIG. 9] is a cross-sectional view of the nozzle.

[FIG. 10 shows a scanning electron micrograph of powder soy sauceobtained by a manufacturing method of an embodiment.

[FIG. 11] is an enlarged scanning electron micrograph of the powder soysauce of FIG. 10.

[FIG. 12] is a scanning electron micrograph of dry powder soy sauceobtained by a conventional manufacturing method.

[FIG. 13] is a diagram showing the correspondence relation between thesurface state of a dry powder soy sauce sample and an element analysisresult of the surface layer.

[FIG. 14] is a diagram showing the element analysis result of thesurface layer based on a reflection electron image of a conventional drypowder soy sauce sample.

[FIG. 15] is a scanning electron micrograph the embodiment.

[FIG. 16] is a scanning electron micrograph of the conventional example.

[FIG. 17] is a sketch of the micrograph of the dry powder soy sauce ofthe embodiment.

[FIG. 18] is sketch of the micrograph of the dry powder soy sauce of theembodiment.

[FIG. 19] is a micrograph of the dry powder soy sauce of the embodiment.

[FIG. 20] is a micrograph of the dry powder soy sauce of the embodiment.

[FIG. 21] is a micrograph of the dry powder soy sauce of the embodiment.

[FIG. 22] is a micrograph of the dry powder soy sauce of the embodiment.

[FIG. 23] is a sketch of a micrograph of the dry powder soy sauceobtained by the conventional method.

[FIG. 24] is a sketch of a micrograph of the dry powder soy sauceobtained by the conventional method.

[FIG. 25] is a micrograph of the dry powder soy sauce obtained by theconventional method.

[FIG. 26] is a micrograph of the dry powder soy sauce obtained by theconventional method.

[FIG. 27] is a micrograph of the dry powder soy sauce obtained by theconventional method.

[FIG. 28] is a micrograph of the dry powder soy sauce obtained by theconventional method.

DESCRIPTION OF REFERENCE NUMERALS

1 main body of drying tower

2 spray nozzle

3 pump

4 raw material tank

5 a heater

6 duct

7 cyclone

8 blower

9 exhaust processing device

17 electric heater

D drain

d dry powder soy sauce

dn downward flow

m fog drip

r raw material soy sauce

S1, S2 temperature sensor

u upward flow

BEST MODES FOR CARRYING OUT THE INVENTION

An embodiment of the present invention will be described hereunder withreference to the accompanying drawings.

FIG. 1 is a manufacturing apparatus of an embodiment.

In FIG. 1, reference numeral 1 represents the main body of a dryingtower, and a spray nozzle 2 (two fluid type spray nozzle) is connectedto the upper portion of the drying tower main body 1. A heater 5 a and apump 3 are successively connected to the spray nozzle 2, and a tank 4filled with soy source r is connected to the pump 3. The soy sauce r inthe tank 4 is pressurized by the pump 3, heated by the heater 5 a,passed through a pipe 5, supplied to the spray nozzle 2 everypredetermined amount, and sprayed into the tower main body 1 to formfine fog drips m. The heater 5 a is interposed because whenlow-temperature soy sauce is directly sprayed, dry powder soy saucecannot be smoothly formed and thus there is a risk that explosivevaporization may occur in some cases.

The drying tower main body 1 is designed to be relatively long andvertically cylindrical because low-temperature drying is applied, and acylindrical apparatus of 0.5 m to 1 m in diameter and 5 m to 10 m inheight is used, for example. Therefore, the time for which the fog dripsmove downwardly in the tower main body 1 is set to be long so thatpowder materials can be sufficiently formed by even the low-temperatureheating.

FIGS. 2(A) and 2(B) are partially longitudinally-sectional views of thedrying tower main body, and FIG. 3 is a diagram showing a double-layerstructure ceramic layer formed on the drying tower main body. The dryingtower main body 1 is formed of aluminum. Alumina ceramic layer C1 isthermally sprayed to the outer surface of the drying tower main body 1,and a titanium oxide ceramic layer C2 is thermally sprayed onto thealumina ceramic layer C1 to form the double-layer structure ceramiclayer 21.

A far infrared electric heater 17 is provided on the upper layer of theouter surface of the double-structure ceramic layer 21 through anelectrical insulating layer 22 as shown in FIG. 4. As shown in FIG. 2,the electrical heater 17 is divided into plural stages (17 a, 17 b, 17c) in the longitudinal direction of the drying tower main body 1,whereby the temperature in the longitudinal direction of the tower mainbody 1 can be freely adjusted. Furthermore, as shown in FIG. 1, aplurality of temperature sensors S1, S2 for measuring the temperature inthe drying tower main body 1 and a temperature distribution are providedat least at the upper portion, the intermediate portion and the lowerportion, whereby the temperature in the drying tower main body 1 can bewholly controlled in a comprehensive manner.

Furthermore, the inner surface of the tower dry main body 1 is coatedwith silicon resin film or fluorocarbon resin film as water repellentresin so that no fog drip of soy sauce does not adhere to the innersurface, and the dry powder soy sauce can be efficiently generated.

FIG. 5 is a longitudinally sectional view of a spray nozzle, FIG. 6 is aV-V sectional view of FIG. 5 and FIGS. 7 to 9 are diagrams showinggeneration of fog drips.

The spray nozzle 2 has a fluid reservoir 31 for temporarily stocking soysauce r from the pump 3, and the fluid reservoir 31 intercommunicateswith a fog drip generator 35 (=fog drip generating space) through pluralfine pores 32. Reference numeral 33 represents a nozzle portion forjetting the supplied soy sauce r like shower.

As shown in FIG. 6, three air introducing paths 36 intercommunicate withthe fog drip generator 35, and the three air introducing paths 36 extendto the center of the fog drip generator 35 so as to intersect to oneanother. Compressed air (air a) which is heated to a predeterminedtemperature is introduced into each air introducing path 36 through aheated air supply unit (not shown).

When the pump 3 is driven and soy sauce r is supplied into the fluidreservoir 31, the supplied soy sauce r is introduced into the nozzleportion 33 having the plural fine pores 32, and supplied as shower-likesoy sauce f into the fog drip generator 35. When air a is introducedfrom the air introducing paths 36 under the above state, eddy flowoccurs in the fog drip generator 35 as shown in FIGS. 7 to 9, and theshower-like soy sauce f is ruffled to form fog drips m. Then, the fogdrips drop from an opening at the lower portion of the fog dripgenerator 35 into the drying tower main body 1.

At this time, the air a introduced from each air introducing path 36 issprayed substantially to the confronting position on the inner surfaceof the fog drip generator 35, and flows along the wall of the bodyportion, so that the fog drips f drops without coming into contact withthe body portion.

A pipe or duct 6 is connected to the lower portion of the drying towermain body 1, and the duct 6 is connected to a supply pipe of a cyclone7. The exhaust pipe 6 a of the cyclone 7 is connected to a blower 8 forstrongly exhausting air. The exhausted air from the blower 8 is led toan exhaust treating apparatus 9, and the exhaust treating apparatus 9has a function of liquefying water vapor occurring in a drying step bymist of cooling water to obtain drain D or separating and removing solidcontents contained in the exhaust air through a filter. Dry powder soysauce d which is separated by the cyclone 7 and obtained as a generatedresultant is accommodated into a tank 7 a connected through a valve.

In FIG. 2(A), the electric heater 17 is divided into three sections 17a, 17 b and 17 c, and these sections can be controlled in temperature soas to be different in temperature among them. For example, thetemperature of the electric heater 17 a can be controlled so that thetemperature T1 at a portion where the spray nozzle 2 exists is equal to60° C., the temperature of the electric heater 17 b can be controlled sothat the temperature T2 at the intermediate portion is equal to 65° C.and further the temperature of the electric heater 17 c can becontrolled so that the temperature T3 at the lower portion is equal to75° C. Here, it is difficult to accurately measure the internaltemperature of the drying tower main body 1 due to the influence of aircurrent, radiation heat, etc. Therefore, there may be adopted a controlmethod of accurately measuring the temperature at the portion of theelectric heater 17 and estimating the internal temperature of the dryingtower main body 1.

In the above construction, it is a main idea that thermal energy isindirectly applied to the spray mist by using far infrared ray radiatedfrom the inside of the drying tower 1 to dry the spray mist. It isneedless to say that thermal energy is also applied by low-temperaturehot air used to atomize soy sauce as a raw material to be treated andradiation of radiant heat from the inner surface of the tower main body.

Next, a method of manufacturing the dry powder soy sauce will bedescribed.

The raw material soy sauce r as liquid type seasoning contains at leastsodium chloride (salt content), seasoning components (total nitrogencontent, etc.) and solvent (alcohol and water), etc., and for example,the following components are contained as “koikuchi (strong) soy sauce”components.

(1) Total nitrogen content: 1.602% . . . (delicious taste component,solid component) asparaginic acid, glutamic acid

(2) Salt content: 16.15% (deliquescence-contributing component, solidcontent)

(3) Saccharide: 3.1% (deliquescence-contributing component) reducingsugar, glucose, arabinose, glycerin, alanine

(4) Solid content: 19.1% (part of solid component serving as nucleus,solid content) inorganic material (potassium, calcium, magnesium,phosphorous, iron, etc.), enzyme

(5) Alcohol content: 2.65% (evaporation vaporization component)

(6) Moisture content: 57.4% (evaporation vaporization component)

In this embodiment, the soy sauce r as raw material is not provided withany excipient for shaping the soy sauce in a powdery form. This isbecause the taste of the soy sauce as the raw material is prevented fromvarying.

As described above, the temperatures T1, T2, T3 (that is, thetemperature at the electric heater side) at the respective sites in thedrying tower main body 1 are adjusted. In this embodiment, thetemperature T3 at the lower side is set to 82° C. (the azeotropictemperature between water and alcohol in soy sauce) or less, thetemperature T1 at the upper site is set to 40° C. or more, and thetemperature T2 at the center portion is set to an intermediatetemperature between the temperature T1 at the upper portion and thetemperature T3 at the lower portion.

At this time, the temperatures are controlled so as to satisfy thefollowing inequality.

10° C.≦|T3−T1|≦30°  (1)

The control of the temperatures T1, T2, T3 at the respective sites inthe drying tower main body 1 is performed by the controller 21 (seeFIG. 1) described above.

Subsequently, the raw material soy sauce r is sprayed into the towermain body 1 together with hot air of about 80° C. while heated at about70° C. by the heater 5 a disposed between the tank 4 and the nozzle 2.

FIG. 2(B) shows a disturbance state of the fog drips in the tower mainbody. A disturbance state is efficiently created in the tower main body1 by air current as shown in FIG. 2(A). As a result, the fog drips ofthe soy sauce r are formed like heavy fog or cloud sea, and each fogdrip floats, rotates and repeats fusion and coalition with other fogdrips while riding air currents (ascending air current and descendingair current) in the drying tower main body 1, whereby the soy sauce r isdried and dry powder soy sauce is obtained.

The actually-obtained dry powder soy sauce grows at a remarkably largersize as compared with the size of fine powder which would be obtained iffine fog drips of soy sauce are independently and individually dried asthey are in the drying tower. That is, it is estimated that even whenthe fog drips are directly dried, dry powder soy sauce having a requiredsize is not formed.

From this observation, the inventor has inferred as follows. The finefog drips of soy sauce sprayed into the drying tower main body 1 float,turn, rotate and impinge against one another under a hot-air atmospherein the drying tower main body (filled with far infrared ray and hotair), and fine fog drips which impinge against one another fuse andmerge together, whereby they gradually grow into assemblies. That is,they grow as if soap bubbles come into contact with one another andadhering soap bubbles grow greatly while floating, turning and falling.In this growth process, outer shells grow gradually so that small soapbubbles which cannot fuse together are enveloped by the growing outershells as if seeds are enveloped. The outer shape of the fine powder asproducts is varied in accordance with the temperature condition and thedisturbing condition described later in this growth process. Thecomponent of soy sauce corresponds the mixture of the solid content, themoisture and the volatile matter content described above, and thus thesolid content contained in the raw material soy sauce forms the skeletonof the powder as the drying proceeds.

That is, the temperature of the fog drips of the soy sauce r sprayedinto the drying tower main body 1 is increased from the intermediateportion to the lower portion while the fog drips concerned is gentlyheated to prevent heat shock, and a large amount of far infrared ray isapplied from the side wall of the drying tower main body 1 during thisprocess, whereby the inside of each fog drip is also evenly heated.Accordingly, granulation of soy sauce is promoted with preventing such adry situation that the internal pressure of the fog drip is increasedand thus phreatic explosion occurs due to drying of only the surface ofthe fog drip.

In this granulation process, the ascending air current U and thedescending air current do can be generated along the wall surface of theinside of the drying tower main body 1 and at the center portion thereofrespectively according to the equation (1), whereby the floating time ofthe fog drips in the tower main body 1 can be adjusted.

Upon summarizing the foregoing, a guideline for setting the dryingcondition (heating condition) is as follows.

The embodiment has been achieved as a result of consideration of theexperience of manufacturing a small amount of dry powder soy sauce, theobservation of electron micrographs, etc., the infer of evaporationbehavior from the outer shape of the dry powder soy sauce, estimation,etc.

(1) When fog drips are dried, water vapor occurs from the fog drips. Inthis case, in order to prevent “water boiling” as much as possible, theheating condition and the heating means for the fog drips of soy sauceare made suitably usable in a low-temperature drying range which has notbeen hitherto applied.

(2) In order to perform a low-temperature drying operation, radiation ofa large amount of “far infrared ray” and a small amount of hot air areused in combination as thermal energy which contributes to drying.

The temperature in the drying tower main body is set to the azeotropicpoint (about 82°) of water and alcohol contained in raw-material soysauce or less, thereby preventing explosive occurrence of water vapor.

Specifically, the temperature is set to 40° C. to 82° C. which is notmore than the azeotropic point of the mixture of water and alcoholconstituting the component of the raw-material soy sauce, and the dryingtemperature is set to this range, preferably set around 60° C.

The reason for this resides in that water vaporization from fog drips ismade further gentle as compared with conventional techniques.

As a result, when the drying temperature is lower than 82° C. as theazeotropic temperature of water and alcohol constituting the componentof soy sauce, it is possible to leave the moisture of about 7% to 8% inthe dry powder soy sauce, and thus the alcohol content and the delicioustaste component contained in soy sauce can remain.

(3) This embodiment aims at the moderate evaporation of water from fogdrips, and thus the length of the drying tower main body is set to belong than a conventional apparatus for performing a high-temperaturedrying operation in order to assist drying.

(4) It is necessary that “ascending air current” along the inner wallsurface of the drying tower main body is naturally generated by thetemperature difference between the upper and lower portions of the towermain body and the heating state is conformed with the dry state.Therefore, the temperature of the drying tower main body is divided intothe upper portion, the intermediate portion and the lower portion orinto the upper and lower portions, and the temperature at the lowerportion side is set to a high temperature while the temperature at theupper portion side is set to be lower than the temperature at the lowerportion side. The temperature difference between the upper portion andthe lower portion is preferably set to 15° C. or more. In this case,when the maximum temperature is lower than 82° C. as the azeotropictemperature of water and alcohol constituting the component of soysauce, this embodiment may be implemented even if the temperaturedifference is equal to about 20° C. to 30° C.

That is, in the actual manufacturing apparatus, if the temperaturedifference between the upper and lower portions is small, ascending aircurrent is not sufficiently generated. If the temperature at the lowerportion side (high-temperature side) is increased to increase thetemperature difference, the temperature difference is out of the abovetemperature range. Accordingly, it is necessary that the temperaturedifference which can be implemented in the above temperature range isset in the actual device.

FIG. 10 shows a scanning electron micrograph of dry powder soy sauceobtained by the manufacturing method of this embodiment, and FIG. 11shows the same scanning electron micrograph when a large-diameterspherical body is enlarged.

In the construction of this embodiment, the fog drips m of the soy saucer float over a long time under the disturbance state in the drying towermain body which is heated so that the fog drips m are set to apredetermined temperature (the azeotropic temperature of water andalcohol in soy sauce or less) and have a predetermined temperaturedistribution based on the formula (1), and each fog drip repeatscontact, fusion and coalition with other fog drips or withsubstantially-dried power soy sauce obtained by evaporation of partialmoisture from the fog drip. Accordingly, as shown in FIG. 10,small-diameter spherical bodies of about 5 to 30 μm in diameter areformed, or large-diameter spherical bodies of about 30 μm or more (morepreferably 40 μm or more) in diameter are further formed from the formedsmall-diameter spherical bodies.

In this embodiment, the small-diameter spherical bodies and thelarge-diameter spherical bodies form mixture bodies. As shown in FIG.11, the surface layer portion of the large-diameter spherical body isformed to have a smooth surface having no rift, and also segregation ofsodium chloride crystals (or consolidated material obtained throughconsolidation of sodium chloride crystals) appears at only two placesand it is suppressed at the other sites. In the photograph, thesegregation of sodium chloride crystals appears with a white spot.

With respect to the sizes of the sodium chloride crystal, etc. based onsegregation, in the case where the size is equal to 5 μm or less as asingle body, deliquescence can be suppressed to a low level even when aplurality of crystals, etc. appear on the surface layer portion of thespherical body. Furthermore, in order to suppress deliquescence to a lowlevel, the area of the surface layer portion covered by sodium chloridecrystals, etc. may be practically suppressed to substantially 30% orless in area ratio with respect to the total surface area of the wholelarge-diameter spherical body, more preferably to 15% or less in arearatio and further more preferably to a value less than severalpercentages.

In this case, even when the sodium chloride crystals, etc. absorbmoisture, they are disposed to be physically far away from one another,and thus they would not cooperate with one another even if moisture(saturated salt solution) adheres to the surface of each of the sodiumchloride crystals, etc. Therefore, the moisture is diffused to the airagain with no increase of the amount of adhering moisture, and a largeamount of moisture can be stocked, so that consolidation of sodiumchloride crystals which causes deliquescence grows hardly.

Here, the segregation to the surface layer portion is suppressed becauseit is estimated that sodium chloride contained in raw-material soy saucedoes not move to the surface layer side of the spherical body at a dashtogether with water due to the slow drying operation, and thus sodiumchloride evenly stays at each portion.

The dry powder soy sauce of this embodiment has a high residual moisturecontent of 7 to 9%, and thus sodium chloride (or chlorine ion and sodiumion) is evenly held in each spherical body, so that sodium chloride ishardly crystallized.

Here, the comparison with dry powder soy sauce manufactured by theconventional manufacturing method will be described.

FIG. 12 is a scanning electron micrograph of dry powder soy sauce basedon the conventional manufacturing method.

As shown in FIG. 12, segregation of sodium chloride crystals appearseverywhere (at white-colored places indicated by a reference characterb) on the surface layer portion of the large-diameter spherical body,and it is observed that segregation of sodium chloride crystals appearsubstantially evenly over the whole area of the surface layer portion.When the dry powder soy sauce based on the conventional manufacturingmethod is eaten with relish, it tastes strongly salty as it supports theabove observation.

On the other hand, with respect to the dry powder soy sauce of thisembodiment, the segregation of sodium chloride crystals is observed atonly two places a within the range of the resolution (≈1 μm) of themicrograph on the surface layer portion of the large-diameter sphericalbody and no broad segregation is observed even when the large-diameterspherical body has a diameter of 100 μm or more. When the dry powder soysauce of this embodiment is eaten with relish, the salty taste issuppressed and it tastes mild and mellow as it supports the aboveobservation.

FIG. 13 is a diagram showing the association between the surface stateof the dry powder soy sauce and a element analysis result of the surfacelayer (about 1 μm from the surface) in this embodiment. Here, FIG. 13(A)shows a BEI (Back scattering Electron Image), FIG. 13(B) is a diagramshowing a distribution state of chlorine atoms (Cl) by EDS (EnergyDispersive X-ray Spectroscopy), and FIG. 13(C) is a diagram showing adistribution state of sodium atoms (Na) by EDS.

According to the BEI image as shown in FIG. 13(A), the segregation ofsodium chloride crystals is not observed in appearance. In the BEIimage, when sodium chloride crystals exist, a whitish portion isapparently observed on the surface of the large-diameter spherical body(substantially 80 μm in diameter) of dry powder soy sauce shown at thecenter portion of FIG. 13(A). However, it is not apparently observed inFIG. 13(A). Furthermore, with respect to the element analysis, whenattention is paid to the large-diameter spherical body (substantially 80μm in diameter) of the dry powder soy sauce shown at the center portionof FIG. 13(A), it is found that chlorine atoms (Cl) are substantiallyevenly dispersively distributed on the large-diameter spherical body asshown in FIG. 13(B). If sodium chloride crystals exist, the density ofthe dots of the chlorine atoms (Cl) would increase and thus the blackcolor of the surface of the large-diameter spherical body would becomedarker. However, this is not apparently observed in FIG. 13(B).

Likewise, with respect to sodium atoms (Na), it is found in FIG. 13(C)that the sodium atoms are substantially evenly dispersively distributedon the surface of the large-diameter spherical body of the dry powdersoy sauce shown at the center portion of FIG. 13(A). In this case, ifsodium chloride crystals exist, the density of the dots of the sodiumatoms (Na) would increase and thus the black color of the surface of thelarge-diameter spherical body would become darker. However, this is notapparently observed in FIG. 13(C).

FIG. 14 is a diagram showing an element analysis result of the surfacelayer (about 1 μm from the surface) based on a reflection electron imagein dry powder soy sauce samples of the conventional example. Here, FIG.14(A) shows a BEI image, FIG. 14(B) is a diagram showing a distributionstate of chlorine atoms (Cl), and FIG. 14(C) is a diagram showing adistribution state of sodium atoms (Na). According to the BEI imageshown in FIG. 14(A), many white portions are apparently observed hereand there on the surfaces of samples, and a state which is estimated asa segregation state of sodium chloride is observed in the conventionalsamples. When attention is paid to a large-diameter spherical body ofconventional dry powder soy sauce (the large-diameter spherical bodyhaving the largest diameter existing at an obliquely upper left sidewith respect to the center of FIG. 14(A), it is found that chlorineatoms (C1) are clearly distributed into black areas (areas having alarge number of chlorine atoms) and white areas (areas having a smallnumber of chlorine atoms), and chlorine atoms exit unevenly and locallyon the surface. Likewise, it is found that sodium atoms (Na) existunevenly and locally on the large-diameter spherical body as shown inFIG. 14(C).

From these results, with respect to the conventional dry powder soysauce, the segregation of sodium chloride is observed on the surfaces,and thus it is estimated that deliquescence caused by sodium chlorideoccurs. As described above, it is estimated that the segregated sodiumchloride induces a strongly salty taste when the dry powder soy sauce iseaten with relish.

On the other hand, with respect to the dry powder soy sauce of thisembodiment, chlorine (Cl) and sodium (Na) are substantially evenlydistributed in a dispersive state in the surface layer existing up toabout 1 μm in depth. However, segregation of sodium chloride crystals isnot found at the surface layer portion, and it is found thatdeliquescence caused by sodium chloride is suppressed. In connectionwith this fact, when the dry powder soy sauce of this embodiment iseaten with relish, the salty taste is suppressed and the dry powder soysauce is mild and mellow in taste as described above. It is estimatedthat this is because the components other than sodium chloride appear onthe surface.

Next, the cross-sectional state of the dry powder soy sauce will bereviewed.

FIG. 15 is a scanning ion micrograph of the cross-section of the drypowder soy sauce of this embodiment which is subjected to FIBprocessing. FIG. 15(A) and FIG. 15(B) are cross-sections of sphericalbodies of different samples. The FIB (Focused Ion Beam) processing is atechnique of irradiating a sample with a gallium (Ga) ion beam tosputter the sample and processing a specific place of the sample whilewatching a scanning ion microscopic image, and it can obtain a smoothcross-section of the sample.

As shown in FIG. 15(A) and FIG. 15(B), in both the samples of the drypowder soy sauce, plural voids k1 appear in cross-sectional view, thesamples are formed to be fleshy, and the issues of the fleshy portionsBD1 are observed to be closely packed and homogeneous.

Accordingly, with respect to the dry powder soy sauce of thisembodiment, it is estimated that there is no segregation of sodiumchloride crystals and also sodium chloride is dispersed stably andevenly even inside the samples, and this also contributes to suppressionof deliquescence.

FIG. 16 shows a scanning ion micrograph of the cross-section of theconventional dry powder soy sauce which is subjected to FIB processing.FIGS. 16(A) and 16(B) show the cross-sections of spherical bodies ofdifferent samples.

As shown in FIGS. 16(A) and (B), plural voids k2 appear incross-sectional view, the tissues of the fleshy portions are nothomogenous in appearance, and component-different portions which areestimated to be crystals K3 of sodium chloride are observed partially.Cracks and recesses are observed on the surfaces of the shell bodies ofsome particles.

Accordingly, it is estimated that segregation of sodium chloride andcracks on the surface affect deliquescence.

The dry powder soy sauce d as a generated resultant material isseparated by a cyclone 7 shown in FIG. 1, and then taken out through thevalve into the tank 7 a.

The dry powder soy sauce d withdrawn from the tank 7 a is put into acontainer (not shown), and the container is covered with a lid. Arequired amount of soy sauce is taken out from the container byreleasing the lid and then the container is covered by closing the lidoccasionally. This opening/closing operation is repeated at several tenstimes or more. Amazingly, in the case of the dry powder soy sauce whichhas been dried at a low temperature (60 to 75° C.) while far infraredray is applied into the drying tower, air is forcedly exchanged from theoutside of the container into the inside of the container every time thelid is released and closed, and thus there is an opportunity thatmoisture invades into the container. However, the dry powder soy saucehas been stocked with no deliquescence even when a very long timeelapses from the manufacturing time. As a result of component analysisand chemical quality estimation of this dry powder soy sauce, it isestimated that the component is not substantially varied from the normalsoy sauce and the original state of taste and flavor as soy sauce iskept.

This dry powder soy sauce contains no dextrin as excipient unlike theconventional dry powder soy sauce, and the dry powder soy sauce as theraw material is sold as goods on the market. The difference between thisdry powder soy sauce and the conventional dry powder soy sauce is alsofound in residual moisture content. The residual moisture content of theformer is equal to 2 to 3%, however, that of the latter is equal to 7 to9%. Since the drying temperature is set to be not more than theazeotropic temperature of water and alcohol in soy sauce as describedabove, it is confirmed that evaporation of water and evaporation ofalcohol in the drying process are suppressed and “umami” (the fifthtaste sensation) component is firmly contained together with alcohol. Inthis case, the residual moisture content may be set to 4 to 12%. This isbecause if the residual moisture content is less than 4%, the “umami”component is escaped together and also if the residual moisture contentis more than 12%, it is impossible to keep a dry-touch powder state.Furthermore, the residual moisture content may be preferably set to 6 to10% from the viewpoint of the containment of the “umami” component andthe maintenance of the powder state. More preferably, the residualmoisture content may be set to 7 to 9% as in the case of thisembodiment, whereby the same level “umami” component as the raw-materialsoy sauce can be felt and the dry-touch powder stage can be kept for along term.

Next, the feature of the dry powder soy sauce of this embodiment will bedescribed in detail in comparison with the conventional dry powder soysauce.

FIGS. 17 and 18 show the illustrations d1 and d2 of the large-diameterspherical bodies of the dry powder soy sauce according to thisembodiment contained in the electron micrograph. FIGS. 19 and 20 showsecondary electron images (SEI) of the dry powder soy sauce.Furthermore, FIGS. 21 and 22 show BEI images (reflection electronimages).

In these cases, FIGS. 19 and 21 show electron micrographs of 350 timesin magnification. FIGS. 20 and 22 show electron micrographs of 750 timesin magnification.

According to the calculation based on the electron micrographs shown inFIGS. 17 to 22, the large-diameter spherical bodies constituting the drypowder soy sauce of this embodiment range from 40 to 120 μm in diameter,and the small-diameter spherical bodies constituting the dry powder soysauce of this embodiment range from about 30 to 40 μm in diameter. Theselarge and small spherical bodies have the following features inappearance.

(1) As shown in FIGS. 19 and 21, spherical bodies which grow greatly(large-diameter spherical bodies) and spherical bodies which do not sogreatly grow (small-diameter spherical bodies) exist under a mixingstate. The number of large-diameter spherical bodies is not so large.

(2) The large-diameter spherical bodies contain spherical bodies havingbeautiful and smooth surfaces as shown in FIGS. 19 and 21, bodies having“tortoiseshell-like or soccer-ball type” projections or pattern on thesurfaces thereof as shown in FIG. 22, and bodies as shown in FIG. 20 theshapes of which are near to those of FIG. 22.

(3) As shown in FIGS. 17 to 22, most of the large-diameter sphericalbodies and the small-diameter spherical bodies form “independentspherical shell bodies”. Neither a crack nor an opening is observed onthe surfaces thereof.

FIGS. 23 and 24 (illustrations of the micrograms) show the features ofconventional commercially-available dry powder soy sauce d3, d4, d5 andd6, FIGS. 25 and 26 show BEI (Backscattering Electron Image) imagesconcerning commercially-available dry powder soy sauce which are pickedup by a scanning electron microscope, and FIGS. 27 and 28 show secondaryelectron images (SEI) of commercially-available dry powder soy saucewhich are picked up by an electron microscope. Here, FIGS. 25 and 27show the images of 350 times in magnification, and FIGS. 26 and 28 showthe images of 750 times in magnification.

The features of the dry powder soy sauce which is dried by theconventional high-temperature applied high-speed heating method will besummed up below.

Estimating the outline dimensions from the micrograms shown in FIGS. 25to 28, the diameter of one fine powder ranges from 100 to 120 μm forlarger-diameter spherical bodies and ranges from about 15 to 25 μm forsmaller-diameter spherical bodies, and bodies having various sizes aremixed. These spherical bodies have the following features in appearance.

(1) The powders d3 to d6 of FIG. 23 and FIG. 24 constitute sphericalbodies. The sizes thereof are not even as a whole, and they are amixture of large and small spherical or potato-like fine powders.

(2) The surface of the spherical body is uneven and rugged, and manyholes or cracks are formed on the outer surface of the spherical body.

(3) Plural small-diameter spherical bodies are contained as granularbodies in a large-diameter spherical body (see FIG. 25 and FIG. 26).

(4) There are little spherical bodies which are individually separatedfrom one another. Many small-diameter spherical bodies are contained ina large-diameter spherical body, and middle-diameter or small-diameterspherical bodies adhere to the surface of a large-diameter sphericalbody as humps, and other spherical bodies further adhere to the abovespherical bodies as if they have the outlook of a cluster of ginger(FIGS. 25 and 26).

That is, according to the drying method of spraying hot air of about120° C. to 260° C. which has been adopted in prior arts, moisture of fogdrips instantaneously suffers a large amount of heat energy when wateris vaporized. It is estimated that water is vaporized at a dash throughthe delivery of the heat energy. In addition, the rapid vaporization ofwater due to this rapid heating is unavoidable in the conventionaldrying method.

Accordingly, it is estimated that water vapor occurring from liquiddroplets generated in the instantaneous or short-time drying processdestructs bone structures which is forming shell bodies as assemblies ofsolid contents which have grown or are growing. That is, moisture infine fog drips vaporizes under the boiling state. This water vapor issurrounded by shell bodies, has no way out and thus vaporizes whiledestructs the shell bodies (phreatic explosion).

Furthermore, according to the prior arts, the shape of the sphericalbodies varies in connection with the magnitude of the injection state ofwater vapor, and particularly explosive injection of water vapordestructs the shell bodies like craters on the surface of the moon.

On the other hand, small-scale injection causes small cracks and holesin the shell bodies. Furthermore, the scale of the surface area, thatis, the contact area with air is affected by the destruction state ofthe shell bodies. Therefore, it is estimated that in connection withthis, the deliquescence is more greatly increased as compared with thedry powder soy sauce of this embodiment.

The reason why the deliquescence of the dry powder soy sauce of thisembodiment is low and the dry-touch state can be secured is as follows.

(1) Segregation of sodium chloride crystals on the surface layer (andinner layer) is suppressed and sodium chloride is distributed to bedispersed on the surface.

(2) A residual moisture content is high, the “umami” component is firmlycontained and sodium chloride is also firmly contained in the innerlayer.

(3) The drying process is executed at a relatively low temperature andfor a long time. Therefore, the large-diameter spherical bodies haverelatively large diameters and hardly aggregate, and further the surfacearea as a whole is, reduced, so that moisture absorption occurs hardly.

From these results, according to the dry powder soy sauce of thisembodiment, the component which causes deliquescence hardly comes intocontact with air or is protected from being exposed, so that thedeliquescence under the use state is reduced and the storage stabilityfor a long term can be enhanced.

The foregoing description relates to an embodiment of the presentinvention, and the following modifications may be made.

In the foregoing description, the commercially available material isdirectly used as the composition of raw material soy sauce, however,this invention is not limited to this style. For example, even “grouts”(produced in a grouts drawing step after matured unrefined soy sauce issqueezed to manufacture non-pasteurized soy sauce and thenon-pasteurized soy sauce is subjected to a heat treatment) occurring ina treatment process before soy sauce is completed can be easily dried,and delicious powder seasoning can be manufactured.

In the foregoing description, soy sauce is adopted as liquid seasoning,however, the application of the present invention is not limited to soysauce.

For example, the present invention may be applied to buckwheat (soba)noodle sauce, ponzu sauce, fish sauce, oyster oil, sauce for grilledmeat, sukiyaki, etc., dressing (particularly, non-oil dressing),ketchup, sauce, demiglace sauce, puree such as tomato puree or the like,soup, pepper sauce, mayonnaise or the like. With respect to seasoningswhich contain a large amount of oil content and thus are creamy in theabove seasonings, they may be temporarily dissolved with solvent such asalcohol or the like, and then sprayed as fog drips into the dryingtower.

Furthermore, in the foregoing description, no additive is added to theraw-material seasoning. In order to further suppress deliquescence, asmall amount of water-repellent for foods can be added. As thewater-repellent for foods may be used edible coating material comprisingplant protein, rosin, sandarac, copal, Arabian gum, zein, soy protein,casein or the like.

1. Dry powder seasoning, characterized by comprising mixtures containinglarge-diameter spherical bodies and small-diameter spherical bodiesgenerated by drying seasoning of a liquid material containing at leastsodium chloride, seasoning components and solvent under a temperaturewhich is not more than the boiling temperature of the liquid material soas to suppress segregation of sodium chloride on surface layer portionsof the large-diameter spherical bodies.
 2. The dry powder seasoningaccording to claim 1, wherein chlorine and sodium are distributed undera substantially uniform dispersive state to suppress the segregation ofsodium chloride.
 3. The dry powder seasoning according to claim 1,wherein the sizes of sodium chloride crystals generated due to thesegregation or consolidated bodies of the crystals are set to be 5 μm orless.
 4. The dry powder seasoning according to claim 1, wherein theseasoning of the liquid material is dried at a temperature which is notmore than the azeotropic point of alcohol and water contained in thesolvent to generate the mixture bodies of the large-diameter sphericalbodies and the small-diameter spherical bodies.
 5. The dry powderseasoning according to claim 1, wherein the surface portions of thelarge-diameter spherical bodies are formed to have smooth surfaceshaving no rift.
 6. The dry powder seasoning according to claim 1,wherein the moisture content of each mixture body ranges from 4% to 12%by weight.
 7. The dry powder seasoning according to claim 1, wherein thediameter of the large-diameter spherical bodies is equal to 40 μm ormore.
 8. A method of drying seasoning of a liquid material containing atleast sodium chloride, seasoning components and solvent to manufacturedry powder seasoning, characterized by comprising: spraying theseasoning of the liquid material into a drying tower so as to obtain fogdrips of the seasoning, the drying tower being controlled so that thetemperature in the main body of the tower is not more than the boilingtemperature of the liquid material and the temperature of an inner wallsurface thereof at a high place is lower than the temperature of aninner wall surface thereof at a low place; and drying the fog dripswhile the fog drips are convected vertically in the drying tower.
 9. Thedry powder seasoning manufacturing method according to claim 8, whereinthe temperature in the drying tower is controlled so that thetemperature concerned is not more than the azeotropic point of alcoholand water contained in the solvent, and the seasoning of the liquidmaterial is sprayed into the drying tower so as to obtain fog drips ofthe seasoning.
 10. The dry powder seasoning manufacturing methodaccording to claim 8, wherein a temperature difference is provided tothe inner wall surface of the main body of the drying tower so that thetemperature difference between high and low places ranges from about 10to 30° C., and ascending current is generated along the inner wallsurface by using the temperature difference.
 11. An apparatus for dryingseasoning of a liquid material containing at least sodium chloride,seasoning components and solvent to manufacture dry powder seasoning,characterized by comprising: a drying tower; a raw-material seasoningspraying unit disposed at an upper portion of the main body of thedrying tower; a raw-material seasoning supply device having atemperature control function that is connected to the spraying unit; acyclone connected to a lower portion of the main body of the dryingtower to separate power dry soy sauce; a gas exhaust device for keepingthe inside of the cyclone under a pressure-reduced state; a heating unitsuch as an electric heater or the like provided to the outer surface ofthe main body of the drying tower; a temperature sensor for measuringthe temperature of a required place of the main body of the tower; and acontroller for controlling a heating state of the heating unit so thatthe temperature in the main body of the tower is not more than theboiling temperature of the liquid material and the temperature of aninner wall surface thereof at a high place is lower than the temperatureof an inner wall surface thereof at a low place.
 12. The dry powderseasoning manufacturing apparatus according to claim 11, wherein thecontroller controls the heating state of the heating unit so that thetemperature in the main body of the drying tower is not more than theazeotropic point of alcohol and water contained in the solvent, and thetemperature of the inner wall surface thereof at the high place is lowerthan the temperature of the inner wall surface thereof at the low place.13. The dry powder seasoning manufacturing apparatus according to claim11, wherein the inner wall surface of the main body of the drying toweris subjected to water repellent finishing such as silicon finishing,fluorocarbon resin finishing or the like to prevent adhesion of dropletsto the inner wall surface of the main body of the drying tower.
 14. Thedry powder seasoning manufacturing apparatus according to claim 11,wherein a ceramic layer having a double-layer structure which containsan aluminum-oxide spray layer mainly containing aluminum oxide and atitan-oxide spray layer mainly containing titan oxide formed on thealuminum oxide spray layer is formed on the outer surface of the mainbody of the drying tower, and the heating unit is disposed on the outersurface of the titan-oxide layer.
 15. The dry powder seasoningmanufacturing apparatus according to claim 14, wherein the heating unitis disposed in each of at least three are as sectioned in thelongitudinal direction of the main body of the drying tower through anelectrically insulating layer on the ceramic layer having the doublestructure formed on the outer surface of the main body of the dryingtower, and the controller controls the temperature of each of theheating units independently.